U.S. Pat. No. 8,955,929 B2 and US Patent Application Publication No. 2014/0077677 A1, the inventers of both of which are Holzapfel et al. and which are incorporated herein by reference, disclose mounting devices of drawer slide assembly, wherein the structures disclosed serve mainly to connect a front panel to a drawer sidewall. More specifically, the drawer sidewall is provided with a fastening device 1, which includes a catching device 10 and a main plate 73. The main plate 73 provides a feed path 6 through which a pin of the front panel can be guided to a receiving means 13 of the catching device 10. During displacement along the feed path 6, however, the pin of the front panel may become instable (e.g., may wobble or tilt), thus deviating from the feed path 6, and the pin's failure to move to the receiving means 13 along the predetermined path causes inconvenience to assembly.